Revolution problem

Hi, I'm hoping someone can lend me a hand. I'm having trouble with the revs on my Seat Ibiza TDI 1.9 ATD engine. Normally, when I start it, the needle reads 950 rpm, and then after a while, the engine revs up a bit and the revs stay at 1000 rpm. I don't know what the problem is. Any help would be greatly appreciated. Thanks

Did you check if the lambda sensor is working correctly?
I had a similar problem once; the lambda sensor, or oxygen sensor, was faulty, which caused my car to rev up intermittently.

Also, check the IAC (Idle Air Control) valve; sometimes they get stuck.

Good luck.